1. The Field of the Art
The present invention relates to a spectrofluorimeter.
2. Description of the Related Art
Spectrofluorimeters are used to detect the presence of certain molecular structures in a specimen. Specifically, in the presence of a solution containing a fluorophore, certain molecular structures are known to interact with the fluorophore such that the incident light of a particular wavelength is absorbed and light having a different wavelength is emitted. Measuring the light emitted at the fluorophore wavelength, due to the presence of the molecular structure of interest in the specimen, allows for the determination of the quantity of the molecular structure of interest in the specimen.
For example, ethidium bromide (EtBr) is used a fluorophore to detect the presence of nucleic acids by virtue of its intercalation into the nucleic acid chain. Monochromatic light having a wavelength of 520 nanometers is irradiated on the solution containing the specimen of interest. By measuring the quantity of light emitted at a wavelength of 600 nanometers allows the concentration of the nucleic acid in the specimen to be determined.
While spectrofluorimetry has been known many years, spectrofluorimeters are typically very large in size, delicate and exceptionally expensive. Many reasons for this exist.
One such reason is that spectrofluorimeters typically require a very large, steady state light source. Such a light source generates large quantities of heat, which requires the distance of the light source from the specimen to be quite large. Furthermore, these light sources typically require mechanical choppers and complicated light directing mechanisms. For example, reference is made to U.S. Pat. Nos. 3,832,555 and 4,531,834.
Furthermore, in order to have wide commercial applications, the detectors of the spectrofluorimeter must be adaptable for use with widely available fluorophore dyes. Furthermore, electrical noise generated by the light source is high in spectroflourimeters generally. These factors have inhibited the use of solid state detectors being used in spectrflourimeters. In the past, Hofer Scientific offered a solid state detector spectrofluorimeter, but this spectroflorimeter could only measure Hoechst dyes due to the requirement that it detect in infrared wavelengths. Thus, this spectroflourimeter could not be used to detect wavelengths in the visible spectrum. Also, the specimen itself was destroyed when using the Hoechst dyes.